| periodic motion consisting of one or more vibratory motions that are symmetric about a region of equilibrium, as the motion of a vibrating string of a musical instrument. |
| harmonic motion n. A periodic vibration, as of a violin string, in which the motions are symmetrical about a region of equilibrium. Such a vibration may have only one frequency and amplitude or may be a combination of two or more components. Also called simple harmonic motion. |